1. Field of the Invention
The invention relates generally to methods and devices for conducting fluids and gases within a reduced pressure treatment system. The invention relates more specifically to an inline connector for multi-lumen tubing that allows free rotation of one end of the tubing with respect to the other end of the tubing.
2. Description of Related Art
General Background of Tissue Treatment
Various therapies have been developed over time to facilitate the process of tissue growth and healing. Wound closure is one application of tissue growth and healing. Wound closure generally involves the inward migration of epithelial and subcutaneous tissue adjacent the wound. This migration is ordinarily assisted by the inflammatory process, whereby blood flow is increased and various functional cell types are activated. As a result of the inflammatory process, blood flow through damaged or broken vessels is stopped by capillary level occlusion, whereafter cleanup and rebuilding operations may begin. Unfortunately, this process is hampered when a wound is large or has become infected. In such wounds, a zone of stasis (i.e. an area in which localized swelling of tissue restricts the flow of blood to the tissues) forms near the surface of the wound.
Without sufficient blood flow, the epithelial and subcutaneous tissues surrounding the wound not only receive diminished oxygen and nutrients, but are also less able to successfully fight bacterial infection and, thus, less able to naturally close the wound and heal the tissue. Additionally, some wounds harden and inflame to such a degree that closure by stapling or suturing is not feasible. Examples of wounds not readily treatable with staples or suturing include large, deep, open wounds; decubitus ulcers; ulcers resulting from chronic osteomyelitis; and partial thickness burns that subsequently develop into full thickness burns.
As a result of the shortcomings of mechanical wound closure devices, methods and apparatuses for draining wounds by applying continuous and/or periodic reduced pressures have been developed. When applied over a sufficient area of the wound, such reduced pressures have been found to promote the migration of epithelial and subcutaneous tissues toward the wound. In practice, the application of reduced pressure to a wound typically involves the mechanical-like contraction of the wound with simultaneous removal of excess fluid. In this manner, reduced pressure treatment augments the body's natural inflammatory process while alleviating many of the known intrinsic side effects, such as the production of edema caused by increased blood flow absent the necessary vascular structure for proper venous return.
One important component of a reduced pressure treatment system is the conduit system that connects the reduced pressure source (a vacuum pump, typically) to the tissue contact components (a granular foam layer or other manifolding device, typically) enclosed within a pad or wound dressing. This reduced pressure conduit structure may include a more complex multi-lumen structure in order to provide ancillary conduits for monitoring and alternative treatment regimens. The ability to maintain a clear, consistent, and leak-free connection is important within an effective reduced pressure treatment system. Various efforts have been made in the past to provide suitable conduit configurations to effectively connect the reduced pressure source to the tissue treatment site at the wound bed.
Efforts to Maintain Conduit Connection Integrity
A variety of systems and devices are utilized in the veterinary medicine environment to connect animal subjects to medical instrumentation. In both research and treatment situations it is often necessary to connect electrical wires and tubular conduit lines between stationary instrumentation and the subject animal that is typically moving about an enclosure when not sedated. The use of reduced pressure tissue treatment regimens with animal subjects, both for research purposes (i.e. to develop systems intended for human use) and for veterinary systems intended for animal treatment, has become more frequent. Such reduced pressure tissue treatment systems are implemented on a variety of animals, large and small, from mice and rats to rabbits and sheep.
Inherent in reduced pressure tissue treatment systems is the use of a number of tubular conduit lines connecting the tissue site on the subject animal to stationary instrumentation typically in the form of negative pressure sources and the associated fluid containers. With human patients, it is often possible (although certainly not always possible) to insist upon reduced mobility or even immobile conditions in order to carry out the tissue treatment. With animal patients, this is of course generally not possible at all unless the animal is sedated. As the preference is to permit the tissue to heal over a period of time, it is generally not practical to maintain sedation of an animal to carry out either research or treatment with reduced pressure application. The problems that arise therefore in maintaining an effective connection between the negative pressure instrumentation and the reduced pressure treatment dressing can become complex. A direct connection between the instrumentation and the wound dressing can quickly become disabled with the movement of the subject animal even within a relatively small enclosure. Typically the movement includes not just side to side motion, but rotational motion often in the form of walking circles around the enclosure. A direct link therefore with tubing between the instrumentation and the wound site could never be maintained without some rotationally moveable connection.
Efforts have been made in the past to provide swivel or rotational connections between tubing or other liquid/gas conduits between a patient or subject animal and the associated treatment instrumentation. Where the tubing is a single lumen tube, this swivel connection generally need not be complex. However, where multi-lumen tubing is utilized, maintaining the structural simplicity of the connector becomes more challenging. Many reduced pressure tissue treatment systems do utilize multi-lumen tubing to carry out a number of functions between the instrumentation and the wound site. Typically a large primary lumen is used to conduct the reduced pressure to the wound site and thereby draw out fluids and exudates from the wound bed. Ancillary to this larger primary lumen are typically one or more (often four radially spaced) smaller lumens that serve to provide a clear path between the reduced pressure treatment instrumentation and the wound site for the purpose of measuring pressure or carrying out other similar therapeutic functions. It is important for these ancillary lumens to remain clear in order for accurate pressure measurements to be made and the treatment regimen to be carried out accurately. Many efforts have been made to isolate the primary lumen from the ancillay lumens in order to prevent the clogging or contamination of the smaller ancillary lumens with fluids and solids being withdrawn from the wound bed.
Some past efforts have focused on providing movable instrumentation by positioning the reduced pressure treatment equipment on an elevated turntable that freely rotates above the animal enclosure and enjoys a direct connection (without an inline swivel tubing connector) between the instrumentation and the wound dressing. Such efforts clearly suffer, however, from the complexities associated with maintaining a turntable integrating all of the electronic and electrical components necessary to carry out the reduced pressure treatment regimens prescribed. In addition, such systems generally work only for very large animal subjects as even with the best support structures a greater force is required to initiate the rotation of the entire instrument laden turntable.
A number of problems arise in attempting to provide a swivel connector for a multi-lumen tube of the structure described above. Initially, a certain level of complexity is required in order to address the connections between more than a single lumen, even where the ancillary lumens are positioned radially outward from the primary lumen, as is typically the case. The continuity of all lumens must be maintained through the swivel connection. An added concern, however, is the increased risk of cross-contamination between the larger primary lumen and the ancillary smaller lumens that need to remain clear. Any leakage in the swivel connector structure could cause fluids and solids to find their way into the small ancillary lumens, thereby clogging those lines and reducing or preventing the effectiveness of the reduced pressure treatment system.
One further complication that arises as a result of the application of such reduced pressure treatment systems to veterinary environments is the wide range in animal size that the systems must accommodate. In order to prevent cross-contamination or leakage in general from a tubing connector, it is necessary that the connector be sufficiently sealed. Providing a tight seal, however, works contrary to the general requirement of providing an easily rotatable connection. The smaller the subject animal involved, the more easily rotatable the connection must be in order to be effective. Larger animals and most human subjects may of course readily rotate a tighter connection. Smaller animals and small children may be wholly unable to rotate a tight connection, resulting in an ineffective swivel connector.
There is a significant need therefore for a rotating or swivel connector for use in conjunction with multi-lumen conduit of the type typically utilized in reduced pressure tissue treatment systems. It would be desirable if such a connector could accommodate both large and small animals, as well as human subjects, through an adjustment of the connection and therefore the rotational force required to turn the connection. In addition, because such connectors often become points of fluid and solid material deposits, it would be desirable if such a connector could be constructed of inexpensive and therefore disposable material that would not require the connector to be repeatedly cleaned between uses.